But unless a last-minute commutation is granted by Texas' governor, Wood will be executed by lethal injection on Wednesday night for his role in a deadly robbery 20 years ago.

In 1996, a 22-year-old Wood waited in a pickup truck while his friend Daniel Reneau went inside a gas station in Kerrville, Texas, to steal the store's safe. Reneau ended up killing the clerk during the robbery.

Most states allow a distinction between accomplices and those who physically carry out the crime.

But in Texas, sitting in that truck and taking part in the robbery is enough to get Wood convicted of murder and onto death row.

Wood's attorney, Jared Tyler, has argued there should be a distinction. "It's rare, both in and outside of Texas, for a person to be sentenced to death based on a conviction under this kind of law," he said.

The crime

Reneau was a drifter who showed up in Kerrville during the summer of 1995. By November of that year, he met Wood through a friend, after couch-surfing and motel-hopping around town.

The pair eventually moved into a trailer together along with their girlfriends. Wood's girlfriend, Nadia Mireles, noticed Reneau engaging in "erratic and threatening" behavior once the foursome started living under one roof, court documents say. Reneau had started arming himself and committing crimes.

In December 1995, Wood and Reneau stole firearms and stored them in the trailer.

Then came the plan to steal the safe from the Texaco gas station after Wood and Reneau befriended the clerks who worked there.

Kris Keeran, the clerk Reneau would eventually shoot, allowed the two to hang around the store, scratching lottery tickets. The three of them, along with the assistant manager, discussed "how to defraud the store of money," according to court documents. Keeran later changed his mind about stealing from the store, the filing says, which frustrated Reneau.

Sitting in a borrowed pickup truck outside the gas station in the early morning of January 2, 1996, Wood waited for Reneau to steal the safe.

His defense attorneys have argued, numerous times, that Wood did not know Reneau was carrying a gun and would subsequently shoot Keeran.

Reneau was executed in 2002.

The law of parties

The Texas statute commonly referred to as the "law of parties" abolishes "distinctions between accomplices and principals...and each party to an offense may be charged and convicted without alleging that he acted as a principal or accomplice."

Crucially, it adds: "If, in the attempt to carry out a conspiracy to commit one felony, another felony is committed by one of the conspirators, all conspirators are guilty of the felony actually committed, though having no intent to commit it..."

The law is not unique to Texas. In some states, it is called "accomplice liability" or "Pinkerton liability" resulting from the 1946 US Supreme Court case Pinkerton vs. United States, according to the National Coalition Against the Death Penalty.

The statute closest to Texas' law of parties is on the books in Georgia, NCADP says. In September 2015, Georgia executed Kelly Gissendaner, who was convicted of murder, for persuading her lover to kill her husband in 1997.

Mark Bennett, a criminal defense lawyer who has worked in Texas for over two decades, made the point that the situation is black and white in Texas because there are no accessories or accomplices to crimes in Texas. "Either you take some role in the crime or you don't," he explained, "and so, there is no way for Wood to be an accessory to murder."

The last man to be convicted and executed under the "law of parties" statute in Texas was 34-year-old Robert Lee Thompson on November 19, 2009. His co-defendant, Sammy Butler, killed a store clerk whom the two were robbing. Butler is serving a life sentence. Thompson did shoot another store clerk in the robbery attempt and that man lived.

Wood's final days

Charles Keeran, the father of the gas station clerk killed by Reneau, said he "originally wished for Reneau and Wood to be executed, [but he] changed his mind after Reneau's execution," according to The Dallas Morning News.

Keeran told the Dallas newspaper that living in prison is a better punishment, and that death was the "easy way out."

CNN made repeated attempts to contact the Keeran family but was not able to reach them for a comment.

Terri Been, Wood's sister, said she grew up a conservative Republican but has spent the past 20 years fighting to change the death penalty laws, which she believed in for much of her adolescence.

She told CNN it feels like the entire family is in its own personal jail cell.

"I scream and scream and talk and talk and nobody listens," she said, crying through her words.

Both Been and Wood's lawyer, Tyler, say Wood has a learning disability and an IQ of 80. This was the reason for a stay of execution in 2008, to give the defense time to argue Wood's inability to comprehend actions and words at an adult level.

"Even if Jeff learns something and can say it back right away, the next day he'll forget everything," Been said.

Page Pate, a constitutional law expert, said Wood's team is thinking along the correct lines by arguing in the latest clemency petition that Wood was party to the crime and there was a lack of intent to kill. His criminal intent was not to take anyone else's life, Pate said.

Tyler is optimistic the courts will hear Wood's out. "I'm not aware of another case in which a person has been executed with as little culpability and participation as Mr. Wood has," he said.

The office of Texas Attorney General Ken Paxton told CNN it does not comment on pending litigation and that "Attorney General Paxton will, as always, enforce the law as written."

Jeff Wood's friends and family delivered the petition for clemency to Gov. Greg Abbott and the Texas Board of Pardons and Paroles on Thursday, the family announced on its website.

The parole board typically makes a recommendation to the governor to stay or continue with the execution a few days before the scheduled date. The board declined to comment on the Wood case.